Single optic for low light and high light level imaging

ABSTRACT

The present disclosure relates to multiple view optical systems. An example optical system includes at least one primary optical element configured to receive incident light from a scene and a plurality of relay mirrors optically coupled to the at least one primary optical element. The optical system also includes a lens optically coupled to the plurality of relay mirrors, and an image sensor configured to receive focused light from the lens. The image sensor includes a first light-sensitive area and a second light-sensitive area. The primary optical element, the plurality of relay mirrors, and the lens interact with the incident light to form a first focused light portion and a second focused light portion. The first focused light portion forms a first image portion of the scene on the first light-sensitive area and the second focused light portion forms a second image portion of the scene on the second light-sensitive area.

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims the benefit of U.S. patent applicationSer. No. 15/856,194, filed Dec. 28, 2017, the content of which isherewith incorporated by reference.

BACKGROUND

Unless otherwise indicated herein, the materials described in thissection are not prior art to the claims in this application and are notadmitted to be prior art by inclusion in this section.

High-dynamic range imaging may be performed by capturing a plurality ofimage frames of a common scene, each having a different exposurecondition. The plurality of image frames may be combined in atone-mapping process to provide a high-dynamic range image that includesimage details of the common scene over a broader dynamic range thanotherwise possible with the underlying image sensor.

Alternatively, high-dynamic range imaging may be performed with multiplecameras that could each capture an image of the common scene at anidentical or similar time. The images captured by the multiple camerascould be combined in a tone-mapping process.

However, these systems and methods for high-dynamic range imaging mayrequire long exposure times (e.g., to capture a plurality of images) orcomplex hardware setups (e.g., multiple cameras). Furthermore,conventional techniques may include capturing the multiple images atdifferent times. In such cases, asynchronous image acquisition may posechallenges when capturing rapidly changing scenes.

SUMMARY

The present disclosure relates to multiple view range imaging withoptical systems that may include a common optical path and a singleimage sensor. The optical system may include a primary optical elementand one or more reflective relay surfaces configured to split incidentlight from a common scene so as to be incident on two differentoptically-sensitive areas on the single image sensor. Such an opticalsystem may provide high-dynamic range, hyper-spectral sensing, or othersynchronous image capture operations without long exposure times orcomplex hardware.

In a first aspect, an optical system is provided. The optical systemincludes at least one primary optical element configured to receiveincident light from a scene. The optical system also includes aplurality of relay mirrors optically coupled to the at least one primaryoptical element. The optical system also includes a lens opticallycoupled to the plurality of relay mirrors. The optical system alsoincludes an image sensor configured to receive focused light from thelens. The image sensor includes a first light-sensitive area and asecond light-sensitive area. A combination of: the at least one primaryoptical element, the plurality of relay mirrors, and the lens interactswith the incident light so as to form a first focused light portion anda second focused light portion. The first focused light portion forms afirst image portion of the scene on the first light-sensitive area. Thesecond focused light portion forms a second image portion of the sceneon the second light-sensitive area. The first and second light-sensitiveareas are non-overlapping.

In a second aspect, an optical system is provided. The optical systemincludes a lens body, which includes an opening at a distal end of thelens body. The opening is configured to receive light from a scene. Theoptical system also includes a primary optical element within the lensbody. The optical system further includes a plurality of relay mirrorsoptically coupled to the primary optical element. The primary opticalelement is configured to reflect light from the scene toward theplurality of relay mirrors. The plurality of relay mirrors areconfigured to form respective portions of relay light from the lightfrom the scene. The optical system yet further includes a lens opticallycoupled to the plurality of relay mirrors and an image sensor with afirst light-sensitive area and a second light-sensitive area. The lensinteracts with the respective portions of relay light so as to form afirst focused light portion and a second focused light portion. Thefirst focused light portion forms a first image portion of the scene onthe first light-sensitive area and the second focused light portionforms a second image portion of the scene on the second light-sensitivearea. The first and second light-sensitive areas are non-overlapping.The optical system additionally includes a controller having a memoryand at least one processor. The controller executes instructions storedin the memory so as to carry out operations. The operations includereceiving the first focused light portion at the first light-sensitivearea and determining the first image portion based on the received firstfocused light portion. The operations also include receiving the secondfocused light portion at the second light-sensitive area. The operationsyet further include determining the second image portion based on thereceived second focused light portion. The operations additionallyinclude determining at least one high-dynamic range image based on thefirst image portion and the second image portion.

Other aspects, embodiments, and implementations will become apparent tothose of ordinary skill in the art by reading the following detaileddescription, with reference where appropriate to the accompanyingdrawings.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 illustrates an optical system, according to an exampleembodiment.

FIG. 2A illustrates an optical system, according to an exampleembodiment.

FIG. 2B illustrates an optical system, according to an exampleembodiment.

FIG. 3 illustrates a composite image, according to an exampleembodiment.

DETAILED DESCRIPTION

Example methods, devices, and systems are described herein. It should beunderstood that the words “example” and “exemplary” are used herein tomean “serving as an example, instance, or illustration.” Any embodimentor feature described herein as being an “example” or “exemplary” is notnecessarily to be construed as preferred or advantageous over otherembodiments or features. Other embodiments can be utilized, and otherchanges can be made, without departing from the scope of the subjectmatter presented herein.

Thus, the example embodiments described herein are not meant to belimiting. Aspects of the present disclosure, as generally describedherein, and illustrated in the figures, can be arranged, substituted,combined, separated, and designed in a wide variety of differentconfigurations, all of which are contemplated herein.

Further, unless context suggests otherwise, the features illustrated ineach of the figures may be used in combination with one another. Thus,the figures should be generally viewed as component aspects of one ormore overall embodiments, with the understanding that not allillustrated features are necessary for each embodiment.

I. Overview

To increase the dynamic range of an image capture system, an opticaldevice can be provided that creates two images (e.g., multiple views) ofthe same scene but with different light intensities or other distinctproperties of incident light on two different portions of an imagesensor. The optical device could be, for example, an internal beamsplitter (e.g., a total internal reflection beam splitter) that includesa 99% reflective surface and a 1% reflective surface. The reflectionsfrom these two surfaces can create two separate images of the same sceneincident upon the same image sensor, with one image having 1% of thelight intensity of the other image. In some embodiments, a device (e.g.,a light baffle) that prevents bleeding of light between differentregions of the image sensor may be used.

The present disclosure provides multiple views of the same scene. Eachof the views could be captured at substantially the same time by thesame image sensor, which may have a relatively low dynamic range (ascompared to higher-quality image sensors). By utilizing an opticalsplitter and/or other types of reflective optical elements, multipleviews of the same scene could be projected onto the same image sensor.

In some embodiments, each different view of the scene could interactwith a different filter (e.g., neutral density, polarization, color,etc.). Such systems could be beneficially utilized to provide desireddisparities between color, polarization, etc.

While various applications of such image capture systems arecontemplated, specific applications may include imaging systems utilizedby autonomous and/or semi-autonomous vehicles. Namely, in drivingscenarios, vehicles may encounter high-dynamic range lighting conditions(bright sun and relatively dim traffic light, or dark night and brightoncoming headlights). As such, the single optic, multiple-view opticalsystems described herein could be incorporated into a vehicle (e.g.,coupled to an exterior or interior surface of the vehicle) and may beoperable to provide better and/or more reliable identification ofobjects, hazards, and/or other features in an environment of thevehicle.

II. Example Optical Systems

FIG. 1 illustrates an optical system 100, according to an exampleembodiment. The optical system 100 includes a primary optical element110. The primary optical element 110 is configured to receive incidentlight 101 from a scene.

In an example embodiment, the optical system 100 could include avehicle. In such a scenario, at least some other elements of opticalsystem 100 could be located on or inside the vehicle, which couldinclude a semi- or fully-autonomous vehicle. For instance, some elementsof the optical system 100 could be fixedly or removeably attached to aroof, side mirror, front, side, rear, or any other exterior portion ofthe vehicle. Additionally or alternatively, some elements of the opticalsystem 100 could be coupled to an interior surface or portion of thevehicle. In an example embodiment, some elements of the optical system100 could be fully or partially attached to an interior cabin of thevehicle and may be arranged to have a forward-facing field of view withrespect to a driving direction of the vehicle. Other attachmentlocations and/or field of view orientations are contemplated.

The optical system 100 also includes a plurality of relay mirrors 120that are optically coupled to the primary optical element 110. Theoptical system 100 additionally includes a lens 130 optically coupled tothe plurality of relay mirrors 120. Yet further, the optical system 100includes an image sensor 140 configured to receive focused light fromthe lens 130.

In some embodiments, the primary optical element 110 could include areflective surface (e.g., such as a mirror) that can reflect theincident light 101 in a desired manner (e.g., toward the plurality ofrelay mirrors 120). In an example embodiment, the primary opticalelement 110 could be disposed within a lens tube or lens body in anannular arrangement along an inner wall of the lens tube. In such ascenario, the reflective surface of the primary optical element 110could be angled so as to reflect the incident light 101 toward theplurality of relay mirrors 120. However, other arrangements ordispositions of the primary optical element 110 are possible andcontemplated. Furthermore, while some embodiments in this disclosure mayinclude a single primary optical element, other embodiments may includea plurality of primary optical element. While the primary opticalelement 110 is described herein as possibly including one or morereflective surfaces, it will be understood that the primary opticalelement 110 could be another type of optical element configured todirect incident light toward the plurality of relay mirrors 120. Assuch, the primary optical element 110 could include one or more opticalfibers, prisms, waveguides, lenses, among other possibilities.

In some examples, the primary optical element 110 and the plurality ofrelay mirrors 120 could be arranged about a common optical axis. In sucha scenario, the primary optical element 110 could include an angledannular mirror surface configured to reflect light toward the pluralityof relay mirrors 120.

The plurality of relay mirrors 120 can include respective reflectivesurfaces, which could be configured to direct respective portions ofrelay light (e.g., first relay light 103 and second relay light 104)toward the lens 130.

In some embodiments, the respective reflective surfaces of the pluralityof relay mirrors 120 and the primary optical element 110 could be formedwith a metallic coating or a high-reflection (HR) dielectric coating(e.g., a periodic stack of alternating high- and low-index of refractionmaterial). In some scenarios, an anti-reflection (AR) coating may beapplied to the respective reflective surfaces and/or other opticalelements described in the present disclosure.

The image sensor 140 includes a first light-sensitive area 142 and asecond light-sensitive area 144. The respective light-sensitive areas ofthe image sensor 140 could include a plurality of light-sensitiveelements (e.g., pixels). In such a scenario, at least one pixel of theplurality of pixels could include: a complementary metal-oxidesemiconductor (CMOS) sensor, a charge-coupled device (CCD) sensor, asilicon photomultiplier (SiPM), a single photon avalanche detector(SPAD), or an avalanche photoconductor. Other types of light-sensitiveelements, or more generally, electromagnetic spectrum-sensitive elements(e.g., micro-bolometers), are possible and contemplated in relation tothe present disclosure.

The first light-sensitive area 142 could encompass a first plurality ofpixels and the second light-sensitive area 144 could encompass a secondplurality of pixels. In some embodiments, a third plurality of pixelscould be arranged between the first plurality of pixels and the secondplurality of pixels. That is, the third plurality of pixels couldinclude pixels of the image sensor 140 that are in an intervening areabetween the first light-sensitive area 142 and the secondlight-sensitive area 144.

In some embodiments, the image sensor 140 could include a relativelylow-dynamic range image sensor compared to the scene to be imaged. Insuch a scenario, the scene could include a wide dynamic range spanningmultiple octaves, and may even be discontinuous. For example, the scenecould range from 5-1000 lux in one region of the scene and range from5000-6000 lux in other regions of the scene. As an example, the brightportions of the scene could correspond to a bright daytime sky. In sucha scenario, the relative dim portions of the scene could correspond toshadowed ground or other dark objects. It will be understood that otherlight levels are possible and contemplated herein.

In an example embodiment, a combination of: the primary optical element110, the plurality of relay mirrors 120, and the lens 130 interacts withthe incident light 101 so as to form a first focused light portion 105and a second focused light portion 106. The first focused light portion105 forms a first image portion of the scene on the firstlight-sensitive area 142. The second focused light portion 106 forms asecond image portion of the scene on the second light-sensitive area144. The first light-sensitive area 142 and the second light-sensitivearea 144 are non-overlapping.

In some embodiments, the plurality of relay mirrors 120 includes a firstreflective surface and a second reflective surface. In such a scenario,the first light-sensitive area 142 receives the first focused lightportion 105 via the first reflective surface and the secondlight-sensitive area 144 receives the second focused light portion 106via the second reflective surface. In some cases, the first reflectivesurface can have a higher reflectivity than the second reflectivesurface, or vice versa.

In some examples, the optical system 100 may include a light baffle 160between the first light-sensitive area 142 and the secondlight-sensitive area 144. The light baffle 160 could include, forexample, an opaque material configured to absorb or block light. Thelight baffle 160 could be located between the first light-sensitive area142 and the second light-sensitive area 144. In such a scenario, thelight baffle 160 could include a wall portion between the respectivelight-sensitive areas. However, the light baffle 160 could take othershapes and forms.

In various embodiments, the first focused light portion 105 has a firstlight intensity and the second focused light portion 106 has a secondlight intensity. In such a scenario, the first light intensity could beat least ten times greater than the second light intensity. For example,the second light intensity could be about one percent of the first lightintensity. Other light intensity differences—both smaller and larger—arepossible and contemplated in the present disclosure.

In scenarios where the optical system 100 is coupled to a vehicle, theimage sensor 140 could be operable to capture images of at least aportion of an environment of the vehicle.

The optical system 100 could also include a controller 150. In anexample embodiment, the controller 150 could include at least oneprocessor 152 and a memory 154. The controller 150. The controller 150may include a computer disposed on a vehicle, an external computer, or amobile computing platform, such as a smartphone, tablet device, personalcomputer, wearable device, etc. Additionally or alternatively, thecontroller 150 may include, or be connected to, a remotely-locatedcomputer system, such as a cloud server. In an example embodiment, thecontroller 150 may be configured to carry out some or all of theoperations as various blocks or steps described herein.

As an example, the at least one processor 152 may execute instructionsstored in the memory 154 so as to carry out certain operations. Theoperations may include some or all of the functions, blocks, or stepsdescribed herein. In some embodiments, different computing devices orcontrollers may carry out the various functions, blocks, or stepsdescribed herein, in various combinations.

The operations could include receiving the first focused light portion105 at the first light-sensitive area 142. In other words, a portion ofthe incident light 101 from the scene could be reflected by the primaryoptical element 110 as reflected light 102 toward at least one relaymirror of the plurality of relay mirrors 120. The at least one relaymirror could reflect first relay light 103 toward the lens 130. Aninteraction between the first relay light 103 and the lens 130 couldform the first focused light portion 105. The first focused lightportion 105 could be directed toward, and/or be incident on, the firstlight-sensitive area 142. Receiving the first focused light portion 105at the first light-sensitive area 142 could include actuating a physical(mechanical) shutter and/or triggering an electronic shuttercorresponding to the first light-sensitive area 142.

The operations could also include determining the first image portionbased on the received first focused light portion 105. Put another way,the image sensor 140 and the controller 150 could form the first imageportion based on the light received at the first light-sensitive area142.

The operations can additionally include receiving the second focusedlight portion 106 at the second light-sensitive area. In other words, aportion of the incident light 101 from the scene could be reflected bythe primary optical element 110 as reflected light 102 toward at leastone relay mirror of the plurality of relay mirrors 120. The at least onerelay mirror could reflect second relay light 104 toward the lens 130.An interaction between the second relay light 104 and the lens 130 couldform the second focused light portion 106. The second focused lightportion 106 could be directed toward, and/or be incident on, the secondlight-sensitive area 144. Receiving the second focused light portion 106at the second light-sensitive area 144 could include actuating aphysical (mechanical) shutter and/or triggering an electronic shuttercorresponding to the second light-sensitive area 144.

The operations can yet further include determining the second imageportion based on the received second focused light portion 106. Putanother way, the image sensor 140 and the controller 150 could form thesecond image portion based on the light received at the secondlight-sensitive area 144.

In an example embodiment, the image sensor 140 could be configured toacquire the first image portion and the second image portion atsubstantially the same time. That is, the first image portion could beacquired over the same time period as that of the second image portion.Alternatively, the first image portion could be acquired during a timeperiod that partially-overlaps with the time period during which thesecond image portion is acquired. In other words, the first imageportion and the second image portion could, but need not, be acquiredduring respective non-overlapping time periods.

In an example embodiment, the first image portion and the second imageportion could include information about a substantially common scene andcould be stored as an image data file. The image data file could bearranged in an image file format, such as RAW, JPEG, TIF, GraphicalInterchange Format (GIF), MPEG, or another type of image file format.

The operations also include determining at least one high-dynamic rangeimage based on the first image portion and the second image portion.

The first image portion, the second image portion, and/or the at leastone high-dynamic range image could be stored in the memory 154.Additionally or alternatively, the first image portion, the second imageportion, and/or the at least one high-dynamic range image could betransmitted and/or stored elsewhere.

In some embodiments, the optical system 100 could additionally oralternatively include at least one filter. The at least one filter couldinclude at least one of: a neutral density filter, a polarizing filter,a spectral filter, a band pass filter, a low-pass filter, or a high-passfilter. Other types of transmissive or reflective optical filters oroptical elements configured to interact with light are contemplated inthe present disclosure.

In such a scenario, the at least one filter could be configured tofilter at least one of: the first focused light portion or the secondfocused light portion.

Furthermore, the at least one filter could be optically coupled to atleast one of: the image sensor, the lens, the at least one primaryoptical element, or the plurality of relay mirrors.

FIGS. 2A and 2B illustrate an optical system 200, according to anexample embodiment. Referring first to FIG. 2A, optical system 200 couldinclude a body configured to protect and/or house at least some elementsof optical system 200. For example, a portion of the body could includea lens body 212.

A portion of the lens body 212 could include an opening 213. The opening213 could be at a distal end of the lens body 212. The opening 213 couldbe configured, positioned, and/or shaped so as to receive light from ascene 280. The scene 280 could be a portion of the environment outsidethe optical system 200. Namely, the scene 280 could include a field ofview of the optical system 200.

The optical system 200 could also include a primary optical element 210within the lens body 212. In some embodiments, the primary opticalelement 210 could include a reflective surface (e.g., surfaces 210 a and210 b).

The optical system 200 could additionally include a plurality of relaymirrors 220 and at least one lens 230 within the lens body 212. Theplurality of relay mirrors 220 are optically coupled to the primaryoptical element 210 and the at least one lens 230. For example, incidentlight reflected from the surface 210 a of primary optical element 210could be directed toward—and interact with—a first relay mirror surface220 a of the plurality of relay mirrors 220. Likewise, incident lightreflected from the surface 210 b of primary optical element 210 could bedirected toward a second relay mirror 220 b of the plurality of relaymirrors 220. While only two “pairs” of primary optical element surfacesand relay mirrors are illustrated in FIGS. 2A and 2B, it will beunderstood that additional “pairs” of primary optical element surfacesand relay mirrors are possible and contemplated within the context ofthis disclosure.

In some embodiments, the respective reflective properties of surfaces220 a and 220 b may be different. For example, surface 220 a could havea normalized reflectance of nearly 1 (e.g., 0.98) and surface 220 bcould have a normalized reflectance of 0.02. It will be understood thatsurfaces 220 a and 220 b could have varying normalized reflectancevalues between 1 and 0. Furthermore, the respective reflectance valuesof surfaces 220 a and 220 b could vary based on a characteristic ofincident light, such as wavelength or polarization. For example, atleast one of surface 220 a or 220 b could be configured to reflect adesired wavelength or waveband of light at a different reflectance valueas compared to other wavelengths or wavebands of light. As a result ofthe differing reflectance values of surfaces 220 a and 220 b, differingintensities of reflected light could be provided to the respectiveportions of image sensor 240.

For example, the primary optical element 210 and/or the plurality ofrelay mirrors 220 could be arranged in a continuous or discontinuousannular arrangement with respect to an optical axis 270 of the opticalsystem 200. For example, the primary optical element 210 could include acontinuously curving mirror angled inward so as to reflect incidentlight toward the optical axis and the plurality of relay mirrors 220.Similarly, the plurality of relay mirrors 220 could include a continuoussurface or discontinuous set of surfaces that are angled away from theoptical axis 270 so as to reflect light towards the lens 230.

The optical system 200 includes an image sensor 240. The image sensor240 could include a first light-sensitive area 240 a and a secondlight-sensitive area 240 b. In an example embodiment, the firstlight-sensitive area 240 a and the second light-sensitive area 240 b donot spatially overlap.

The image sensor 240 could include at least one of: a CMOS sensor, a CCDsensor, a silicon photomultiplier (SiPM), a single photon avalanchedetector (SPAD), or an avalanche photoconductor. Furthermore, the imagesensor 240 could include an array of light-sensitive devices or pixels.As described elsewhere herein, the image sensor 240 could be configuredto capture an image from the first light-sensitive area 240 a and thesecond light-sensitive area 240 b over substantially the same timeperiod. In an example embodiment, during an image capture period, thefirst light-sensitive area 240 a may be operated using a different gainsetting (e.g., ISO or sensitivity) as compared to the secondlight-sensitive area 240 b. Other ways to adjust the exposure betweenthe first light-sensitive area 240 a and the second light-sensitive area240 b are contemplated herein.

In an example embodiment, the plurality of relay mirrors 220 can beoptically coupled to the primary optical element 210. Additionally, theprimary optical element 210 could be configured to reflect light fromthe scene 280 toward the plurality of relay mirrors 220. In such ascenario, the plurality of relays mirrors 220 is configured to formrespective portions of relay light from the light from the scene 280.The relay light may be directed toward the lens 230. In someembodiments, the lens 230 could be configured to focus the relay lightonto and/or direct the relay light towards the image sensor 240.

In some embodiments, the optical system 200 could include a light baffle260. The light baffle 260 could include one or more light-absorbing“walls” or portions. The light baffle 260 could be disposed between thefirst light-sensitive area 240 a and the second light-sensitive area 240b. The light baffle 260 could be configured to prevent stray light from“leaking” between the respective light-sensitive areas of image sensor240 or between portions of the optical system 200. Additionally oralternatively, the optical system 200 could include other elementsconfigured to reduce stray light, modify or shape a light field, and/orreduce ghost reflections. Such other elements could include furtherbaffles, stops, mirrors, lens, coatings, light guides, optical fibers,or other optical materials.

In some embodiments, the optical system 200 may include a filter 272.Although FIGS. 2A and 2B illustrate filter 272 as being near a distalend of the lens body 212, other locations for filter 272 are possibleand contemplated herein. For example, filter 272 could be coupled to oneor more surfaces of the primary optical element 210 and/or one or moresurfaces of the plurality of relay mirrors 220. In some embodiments,filter 272 could interact with light received by the firstlight-sensitive area 240 a, but not with light received by the secondlight-sensitive area 240 b, or vice-versa.

FIG. 2B illustrates optical system 200, according to an exampleembodiment. FIG. 2B is similar to FIG. 2A but also illustrates examplelight rays that approximate certain light paths in the optical system200.

The opening 213 may be configured to receive incident light from thescene 280. While the incident light may enter the lens body 212 throughthe entire area of the opening 213, for clarity only two portions ofincident light—a first incident light portion 201 a and a secondincident light portion 201 b—are illustrated here. It will be understoodthat other incident light portions may be received by optical system 200and the present disclosure contemplates all other such portions.

In an example embodiment, the first incident light portion 201 a mayinteract with the primary optical element 210. For instance, the firstincident light portion 201 a may be reflected by surface 210 a anddirected toward the plurality of relay mirrors 220 as reflected light202 a. Namely, the reflected light 202 a could interact with the firstrelay mirror surface 220 a.

In such a scenario, the first relay mirror surface 220 a could reflectlight toward the lens 230 as relay light portion 203 a. The lens 230could interact with the relay light portion 203 a so as to focus therelay light portion 203 a to provide first focused light portion 204 a.The first focused light portion 204 a may be directed toward the firstlight-sensitive area 240 a of image sensor 240.

Similarly, the second incident light portion 201 b may interact with theprimary optical element 210. For instance, the second incident lightportion 201 b may be reflected by surface 210 b and directed toward theplurality of relay mirrors 220 as reflected light 202 b. The reflectedlight 202 b could interact with the second relay mirror surface 220 b.

In such a scenario, the second relay mirror surface 220 b could reflectlight toward the lens 230 as relay light portion 203 b. The lens 230could interact with the relay light portion 203 b so as to focus therelay light portion 203 b and form second focused light portion 204 b.The second focused light portion 204 b may be directed toward the secondlight-sensitive area 240 b of image sensor 240.

The first focused light portion 204 a can form a first image portion ofthe scene 280 on the first light-sensitive area 240 a and the secondfocused light portion 204 b can form a second image portion of the scene280 on the second light-sensitive area 240 b. In some embodiments, thefirst focused light portion 204 a could have a first light intensity andthe second focused light portion 204 b has a second light intensity. Insuch a scenario, the first light intensity is at least ten times greaterthan the second light intensity. Correspondingly, the first imageportion could represent a much brighter image of the scene 280 ascompared to the second image portion.

In some embodiments, the optical system 200 may include a controller(not illustrated in FIG. 2A or 2B). The controller could include amemory and at least one processor. The controller executes instructionsstored in the memory so as to carry out operations. The operations couldinclude receiving the first focused light portion 204 a at the firstlight-sensitive area 240 a. The operations can also include determiningthe first image portion based on the received first focused lightportion 204 a. The operations yet further include receiving the secondfocused light portion 204 b at the second light-sensitive area 240 b.The operations could also include determining the second image portionbased on the received second focused light portion 204 b.

In example embodiments, the controller could be operable to determine atleast one high-dynamic range image based on the first image portion andthe second image portion. For instance, determining at least onehigh-dynamic range image based on the first image portion and the secondimage portion could include application of at least one of: a non-lineartone-mapping algorithm, a non-linear radiance-mapping algorithm, or acolor appearance model. It will be understood that other ways to combinethe first image portion and the second image portion so as to provide ahigh-dynamic range image are possible. For example, the high-dynamicrange image may include fewer under- or over-exposed areas as comparedto either the first or second image portions. The high-dynamic rangeimage could provide greater detail than either the first image portionor the second image portion in certain areas of the image or undercertain operating conditions. For example, the high-dynamic range imagecould provide higher quality object identification information in verybright (e.g., full sun, looking into the sun, actively illuminatedscenes, etc.) or very dark (night) imaging scenarios. Other high dynamicrange scenes such as a night scene with bright headlights or a brightday scene with relatively dim traffic lights are also contemplated. Thatis, the first image portion and the second image portion could becombined or otherwise utilized in such a manner so as to provide morereliable or less ambiguous object identification information.

It will be understood that, while a “first image portion” and a “secondimage portion”—and their combination—are described herein, other numbersof images and/or image portions are possible. For example, a pluralityof light-sensitive areas on the image sensor 240 could be utilized so asto provide a corresponding plurality of image portions. At least some ofthe plurality of image portions could be combined so as to form thehigh-dynamic range image.

Furthermore, while simultaneous image capture of the first image portionand the second image portion is contemplated, other image capturesequences are possible. For example, the first and second image portionscould be captured at different times under different lighting or imagecapture (e.g., exposure) conditions. Also, burst imaging modes arecontemplated within the scope of the present disclosure. That is, aplurality of images could be captured in an image burst (e.g., imagescaptured in quick temporal succession). At least some of the pluralityof images could be combined to provide the high-dynamic range imagedescribed herein. Additionally or alternatively, the system andoperations described herein could provide a plurality of high-dynamicrange images—such as a high-dynamic range image set or video stream.

FIG. 3 illustrates a composite image 300, according to an exampleembodiment. The composite image 300 includes a first image portion 310and a second image portion 320. The first image portion 310 couldinclude a generally-over-exposed image of an outdoor scene. The secondimage portion 320 could include a generally-under-exposed image of theoutdoor scene. In other words, the composite image 300 could include thefirst image portion 310 and the second image portion 320 as being indifferent non-overlapping locations in the composite image 300.Alternatively or additionally, the composite image 300 could include thefirst image portion 310 and the second image portion 320 as being atleast partially overlapping.

As described herein, information from the first image portion 310 andthe second image portion 320 could be combined or otherwise manipulatedso as to provide a high-dynamic range image. For example, in the presentscenario, the high-dynamic range image could provide accurate colorinformation for the illuminated traffic lights, increased detail in theover-exposed regions of the first image portion 310, and increaseddetail in the under-exposed regions of the second image portion 320.Other ways to obtain high-dynamic range information by combining orotherwise utilizing a plurality of images of the same scene arecontemplated herein.

The particular arrangements shown in the Figures should not be viewed aslimiting. It should be understood that other embodiments may includemore or less of each element shown in a given Figure. Further, some ofthe illustrated elements may be combined or omitted. Yet further, anillustrative embodiment may include elements that are not illustrated inthe Figures.

A step or block that represents a processing of information cancorrespond to circuitry that can be configured to perform the specificlogical functions of a herein-described method or technique.Alternatively or additionally, a step or block that represents aprocessing of information can correspond to a module, a segment, aphysical computer (e.g., a field programmable gate array (FPGA) orapplication-specific integrated circuit (ASIC)), or a portion of programcode (including related data). The program code can include one or moreinstructions executable by a processor for implementing specific logicalfunctions or actions in the method or technique. The program code and/orrelated data can be stored on any type of computer readable medium suchas a storage device including a disk, hard drive, or other storagemedium.

The computer readable medium can also include non-transitory computerreadable media such as computer-readable media that store data for shortperiods of time like register memory, processor cache, and random accessmemory (RAM). The computer readable media can also includenon-transitory computer readable media that store program code and/ordata for longer periods of time. Thus, the computer readable media mayinclude secondary or persistent long term storage, like read only memory(ROM), optical or magnetic disks, compact-disc read only memory(CD-ROM), for example. The computer readable media can also be any othervolatile or non-volatile storage systems. A computer readable medium canbe considered a computer readable storage medium, for example, or atangible storage device.

While various examples and embodiments have been disclosed, otherexamples and embodiments will be apparent to those skilled in the art.The various disclosed examples and embodiments are for purposes ofillustration and are not intended to be limiting, with the true scopebeing indicated by the following claims.

What is claimed is:
 1. An optical system comprising: at least oneprimary optical element configured to receive incident light from ascene; a plurality of relay mirrors optically coupled to the at leastone primary optical element; wherein the plurality of relay mirrorsincludes a first reflective surface and a second reflective surface; andwherein the first reflective surface has a higher reflectivity than thesecond reflective surface; a lens optically coupled to the plurality ofrelay mirrors; and an image sensor configured to receive focused lightfrom the lens, wherein the image sensor comprises a firstlight-sensitive area and a second light-sensitive area, wherein acombination of: the at least one primary optical element, the pluralityof relay mirrors, and the lens interacts with the incident light so asto form a first focused light portion and a second focused lightportion, wherein the first focused light portion forms a first imageportion of the scene on the first light-sensitive area and wherein thesecond focused light portion forms a second image portion of the sceneon the second light-sensitive area, wherein the first focused lightportion has a first light intensity and wherein the second focused lightportion has a second light intensity, wherein the first light intensityis different than the second light intensity.
 2. The optical system ofclaim 1, wherein the optical system further comprises a vehicle, andwherein the image sensor is operable to capture images of at least aportion of an environment of the vehicle.
 3. The optical system of claim1, wherein the image sensor comprises a plurality of pixels, wherein atleast one pixel of the plurality of pixels comprises: a CMOS sensor, aCCD sensor, a silicon photomultiplier (SiPM), a single photon avalanchedetector (SPAD), or an avalanche photoconductor.
 4. The optical systemof claim 1, wherein the at least one primary optical element and theplurality of relay mirrors are arranged about a common optical axis. 5.The optical system of claim 4, wherein the at least one primary opticalelement comprises an annular mirror surface configured to reflect lighttoward the plurality of relay mirrors.
 6. The optical system of claim 1,wherein the first light sensitive area receives the first focused lightportion via the first reflective surface and the second light-sensitivearea receives the second focused light portion via the second reflectivesurface.
 7. The optical system of claim 1, further comprising a lightbaffle between the first light-sensitive area and the secondlight-sensitive area.
 8. The optical system of claim 1, wherein thefirst light-sensitive area encompasses a first plurality of pixels andthe second light-sensitive area encompasses a second plurality ofpixels, and wherein a third plurality of pixels is arranged between thefirst plurality of pixels and the second plurality of pixels.
 9. Theoptical system of claim 1, further comprising a controller, wherein thecontroller executes instructions so as to carry out operations, theoperations comprising: receiving the first focused light portion at thefirst light-sensitive area; determining the first image portion based onthe received first focused light portion; receiving the second focusedlight portion at the second light-sensitive area; determining the secondimage portion based on the received second focused light portion; anddetermining at least one composite image based on the first imageportion and the second image portion.
 10. The optical system of claim 1,further comprising at least one filter, wherein the at least one filtercomprises at least one of: a neutral density filter, a polarizingfilter, a spectral filter, a band pass filter, a low-pass filter, or ahigh-pass filter.
 11. The optical system of claim 10, wherein the atleast one filter is configured to filter at least one of: the firstfocused light portion or the second focused light portion.
 12. Theoptical system of claim 10, wherein the at least one filter is coupledto at least one of: the image sensor, the lens, the at least one primaryoptical element, or the plurality of relay mirrors.
 13. An opticalsystem, comprising: a lens body comprising an opening configured toreceive light from a scene; a primary optical element within the lensbody; a plurality of relay mirrors optically coupled to the primaryoptical element, wherein the primary optical element is configured toreflect light from the scene toward the plurality of relay mirrors,wherein the plurality of relay mirrors are configured to form respectiveportions of relay light from the light from the scene; a lens opticallycoupled to the plurality of relay mirrors; an image sensor with a firstlight-sensitive area and a second light-sensitive area, wherein the lensinteracts with the respective portions of relay light so as to form afirst focused light portion and a second focused light portion, whereinthe first focused light portion forms a first image portion of the sceneon the first light-sensitive area and wherein the second focused lightportion forms a second image portion of the scene on the secondlight-sensitive area; and a controller comprising a memory and at leastone processor, wherein the controller executes instructions stored inthe memory so as to carry out operations, the operations comprising:receiving the first focused light portion at the first light-sensitivearea; determining the first image portion based on the received firstfocused light portion; receiving the second focused light portion at thesecond light-sensitive area; determining the second image portion basedon the received second focused light portion; and determining at leastone composite image based on the first image portion and the secondimage portion.
 14. The optical system of claim 13, wherein the firstfocused light portion has a first light intensity and wherein the secondfocused light portion has a second light intensity, wherein the firstlight intensity is at least ten times greater than the second lightintensity.
 15. The optical system of claim 14, wherein determining atleast one composite image based on the first image portion and thesecond image portion comprises applying at least one of: a non-lineartone-mapping algorithm, a non-linear radiance-mapping algorithm, or acolor appearance model.
 16. The optical system of claim 13, wherein theimage sensor comprises at least one of: a CMOS sensor, a CCD sensor, asilicon photomultiplier (SiPM), a single photon avalanche detector(SPAD), or an avalanche photoconductor.
 17. The optical system of claim13, further comprising a light baffle between the first light-sensitivearea and the second light-sensitive area.